Method of extracting moisture from air for blast-furnaces and converters.



No. 746,814. PATENTED DEC. 15, 1903 J. GAYLEY.

METHOD OF EXTRAGTING MOISTURE-FROM AIR FOR BLAST FURNACES ANDCONVERTERS.

' APPLIOATION FILED SEPT. 22 1894. N0 MODEL. 2 SHEETS-SHEET}.

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\ UNITED STATES Patented December 15, 1903.

PATENT OFFICE.

.JAMES GAYLEY, OF BRADDOOK, PENNSYLVANIA.

SPECIFICATION forming part of Letters Patent No. 746,814, dated December15, 1903.

Application filed September 22, 1894.

To all whom away concern: Be it known that 1, JAMES GAYLEY, of Braddock,in the county of Allegheny and State of Pennsylvania, have invented anew and useful Improvement in Methods of Extracting Moisture from Airfor Blast-Furnaces and Converters, of which the following is a full,clear, and exact description, reference being had to the accompanyingdrawings, forming part ofthis specification, in which- Figure 1 shows inelevation, partly in vertical section, apparatus adapted to the practiceofv my invention. Fig.2 is a plan View, on an enlarged scale, oftheair-refrigerating apparatus, one of the chambers being shown inhorizontal section. Fig. 3 is a side elevation of the same, partly invertical section.

My present invention is a subordinate improvement upon a method offeeding air to blast-furnaces or converters, for which I have alreadyobtained Letters Patent of the United States No. 527,844, dated October23, 1894, in which I claim-broadly the method of feeding the air-blastto blast-furnaces or converters, which consists incooling the airartificially to 0 centigrade, thereby causing its moisture to beeliminated or reduced to a small. and practically uniform percentage,feeding the dried air under compression into the furnace'or converter,and maintaining it constantly under compression from the time it leavesthe blowing-engineuntil it enters In said 1 patent the apparatus which Ishow and describe is constructed and arranged so that the air iscompressed before its moisture is extracted, although the method claimsof said application are not limited thereto. I have discovered thatmaterial advantages result if the cooling and drying of the air areperformed before it is compressed. As stated in the specification of mysaid patent, the successfulconduct of all metallurgical operationsdepends to a great extent on the uniformity of the various materialsused in the process. In, operating blast-furnaces and steel-convertersone of the most disturbing influences is the varying amount of moisturein the atmosphere, since in both these processes a large amount of airis consumed for the purpose of oxidation or com bustion. The atmosphereholds in suspension quantities of aqueous vapor varying Serial No.523,762. (No specimens.)

from .20 to 1.6 per cent., and its presence in these metallurgicaloperations is injurious not only because it is decomposed in the partsof the apparatus Where high heat is required, and thus absorbs heat, butthe fluctuations in the quantity of moisture.carried by the air producecorresponding irregularities in the conduct of the process and in thequalityof the product. In the operation of the Bessemer converters themoisture of the atmosphere and its variations in amountare just astroublesome. Its presence in large quantity causes a cooling of themetal-hath, which interfereswith the uniform conduct ofthe process andoften produces wasteful chilled heats. All these sources of irregularityand expense in metallurgical operations are eliminated by use of myinvention, by means of which I furnish for. the furnace or converter anair-blast practically free from atmospheric moisture.

In order to fully understand the application I of this device, I wouldexplain that it is intended to be used with blast-furnaces for thesmelting of ores, with steel-converters for the conversion of ironintosteel; In all of these the air is used solely for the purpose ofoxidation or combustion. Blast-furnaces are now constructed with aheight of ninety feet and a diameter ofItw'enty-two feet. These are keptfull continuously with a mixture of fuel, ore, and flux, and these odorgreat resistance to the penetration of the blast, which is admitted atthe bottom. It notuncommonly requires a pressure of fifteen to twentypounds per square inch in the air-blast to penetrate this column ofmaterial. Likewise in the converter the air is forced through a bath ofmetal, which frequently weighs fifteen tons, and requires a pressure oftwenty-five pounds per square inch .in the blast for economicconversion.

In the practice of my invention I remove the moisture from the air andrender it dry, or so dry at least that the percentage of moisturecontained in the air is small and practically uniform bysubjecting it toartificial refrigeration, so that its temperature shall be reduced to 0centigrade, whereby the moisture is condensed and may be collected andwithdrawn in the form of water, the air being fed to the furnace orconverter under compression from the time it leaves the blowingengineuntil it reaches the furnace.

Referring now to the drawings, 6 is the pipe through which theatmospheric air is admitted to the cooling apparatus. This pipe may beextended and cooled by water or other fluid, preferably externally, ifdesired. From the pipe 6 the air passes into a chamber 7, which is madelarger to give a greater area of contact, in which is a series of pipes,as shown at 8, which extend across the chamber and at their ends openinto chambers shown at 9 and 10. By reason of its greater conductivityof heat the pipes should preferably be made of copper. The water orother fluid for cooling the chamber 7 is admitted by a pipe 12 and afterpassing through the chamber 10 and thence through the pipes 8 emerges atthe outlet-pipe 11. The air being under a constant suction by the enginedoes not expand on entering the chamber 7. A partial deposition of itscontained moisture takes place, which is reduced to a mist by contactwith the refrigerating-surfaces of the pipes. After the air has passedthrough the chamber 7 it may enter a second chamber 13. Chambers 7 and13' are similarly constructed, except that in chamber 13 I prefer toobtain a better chilling effect by the use of anhydrous ammonia .as thecooling agent, and therefore construct the pipes 8 of iron. The coolingagent is preferably anhydrous ammonia furnished by an ice-making.machine of suitable design, which on evaporation produces a very lowtemperature-about below zero.

centigradethough other refrigerants producing intense cold, such ascarbonic anhydrid, may be employed. The cooling liquid passes throughthe chamber 13 in the same manner as described for chamber 7, and isremoved by suitable pipes, as shown. The entering air is cooled bypassing through the chamber 7, and in the chamber 13 under theintensecold produced by the ammonia the temperature of the air is reduced belowthe freezing-point,so that its contained moisture is precipitated on theouter surface of the pipes.8 and collects at the bottom of the chamber,from which it may be drawn oif through suitable pipes. When using arefrigerant, such as anhydrous ammonia, the liquid absorbs heat from theair and is converted intoagas. It is subsequently cooled and restored toa liquid state for further use. It frequently happens that under theintense cold of the expanding ammonia ice is formed on the pipes 8 inchamber 13, and it may be found desirable to construct the chamber 13 induplicate, as shown in Fig. 2, so that when ice is formed in one chamberthe cooling process may be diverted to the other chamber In Fig. 2 areshown valves 21 fordiverting the air from one chamber to another. Thepipe 22 may also be provided with valves, if found advisable. In orderto provide against any of the precipitated moisture being carried alongin suspension by the refrigerated air, I prefer to employ a chamber 16,containing a series of grids 17 with .small metal ribs and preferablyplaced in a slanting position. These grids catch the suspended moistureor water, which can be removed through suitable drain-pipes. The chamber16 is made of sufficient size, so that there is no retardation to theair due to interposition of grids. Having been cooled in the mannerabove described and the moisture extracted, the air is delivered to theblast-engine, from which it is delivered to the blast-furnace orconverter through the various pipes and passages equal to the operation.

In Fig. 1, 18 is the blast-pipe conducting the air to the hot-blaststoves, from which it passes into pipe 19, which conducts it into theblast-furnace, Fig. 1. 20 is the pipe which conducts the air from theblast-engine to the steel-converter. There are some advantages intreating the air for removal of its contained moisture before it isadmitted to the blowing-engine, owing to the fact thatthe compressionincreases the temperature of the air very rapidly, since air at anatmospheric temperature of 60 after passing through an engine andcompressed to twelve or thirteen pounds obtains an increase intemperature of about 150. Consequently when the air is treatedatatmospherictemperatureitrequires a less cooling efiect to reduce it tozero centigrade and less expenditure for cooling appliances. Besides,airat higher temperatures holds the moisture more tenaciously. Anotheradvantage possessed is that the blowingengines are made more efficient,as the air being cooled to a low temperature and its moisture extractedeach cubic foot of air delivered by the engine is richer in oxygen andmore suitable for combustion; but the main advantage consists in itsrequiring a much less expensive cooling apparatus, and thereby renderingit more available for manufacturing.

Many forms of apparatus may be used in the application of this inventionin order to apply it to existing conditions. It is desirable to have theair in contact with pipes as long as possible, and for this purposelarge chambers like rooms in which the cooling.- pipes would act as apartition may be found desirable or it is possible to do all of thecooling with ammonia alone, although it is not so economical, or thecooling fluid may be ammonia in one chamber and brine in the other, andwith smaller volumes of air only one chamber may be used. Thecooling-pipes,

may also be constructed in the form of a coil and of such length as toderive the most economical results from the refrigerant.

It will be readily observed that on account of the air being constantlyin rapid motion,

IIO

due to the suction of the engine and the enormous volume required, themethods usually employed for extracting a portion of the moisture fromsmall volumes of air in applying it to drying grain, cooling rooms,850., are not applicable to blast-furnaces and converters, since in manyof these methods the air is allowed to expand, which in itself is themost serviceable refrigerating process and simplifies the operation to agreat extent, while in my process there is no substantial expansion ofthe air prior to its introduction 1 into the furnace.

The mechanical retardation of the current by partitions andgrids isavoided in my device, the grid-chamber being of such area that the spacebetween the ribs is sufficient to allow the volume to pass throughwithout retardation.

In my apparatus the current of cooling fluids passing through a seriesof pipes is directl y across that of the air-currents, by which Imaintain in this short travel a much lower temperature than in suchappliances where the currents of air and cooling fluid are longitudinal.

The advantages of my invention will be appreciated by those skilled inthe art. By

' rendering the air dry or practically dry by refrigeration, asdescribed above, before it is introduced into the blast-engine andsupplying such dry air in large quantities under constant compression tothe furnace or converter the amount of moisture is made practicallyuniform from day to day and from year to year. It is thus made easy forthe blast-furnace manager to secure uniformity in the character of metalproduced by the furnace notwithstanding varying meteorologicalconditions and without that close supervision which is necessary infurnace practice heretofore in common use.

I claim- The method of feeding air to'blast-furnaces or converters,which consists in drawing the air through a chamber and cooling it insaid chamber to 0 centigrade, thereby causing its moisture to beeliminated or reduced to a small and practically uniform percentage,thereafter causing the dried air to pass into the blowing-engine, thenfeeding the dried air into the furnace or converter, and maintaining itconstantly under compression from the time it leaves the blowing-engineuntil it enters the furnace or converter; substantially as described.

In testimony whereof I have hereunto set myhand.

JAMES GAYLEY.

Witnesses:

W. A. HOLLAND, J. N. GRIFFITH.

